Monday, October 15, 2012

blown-in cellulose - this is where, with the use of a special machine, one fills all the cavities between the studs with a loose-fill cellulose fiber insulation. The benefit this provides over fiberglass is that it behaves more like a liquid during installation. It fills in all the gaps that might be left with fiberglass batting, has greater thermal mass, and is easy to manufacture

open-cell foam - this is a type of spray-on foam. It does not provide air or water-tightness, but is easier to apply as closed-cell foam.

closed-cell foam - this is by far the best and most expensive type of insulation I came across. Similar to the open-cell insulation, a polymer liquid is sprayed onto the walls, and it expands as it cures. This type of foam provides very high R-values as well as creates an air and water-tight seal against whatever surface it covers

In order to get the most benefit out of the properties of the different materials and to save cost, I went with a hybrid approach. All ceilings were sprayed with a 1" layer of closed-cell foam, then the rest covered in fiberglass batting. That gives the benefits of the air-tightness of the foam and saves costs. The 2nd and 3rd floor walls were all given a blow-in cellulose treatment.

Blow-in insulation on walls and closed-cell foam on ceilings

The rafters get filled in with fiberglass

Lastly, there was a bit of an error made in the planning of the downstairs area. Downstairs, much of the the concrete walls are exposed and insulated from the outside of the house. Unfortunately, the city inspector didn't like that there was a section of wall near the top that is not insulated from either side of the house. In order to keep the proper look of the house from the outside, I decided that the downstairs area walls should be framed out and insulated. I lost about 6" from the room, but I don't think it will be noticed.

Monday, October 8, 2012

The siding contractors have finished installing the first of three siding materials on the house - charred cedar. This type of siding originates from an old Japanese technique called shou sugi ban. Traditionally, planks of wood are set on fire and allowed to burn for a few minutes before being extinguished. This creates a dark layer of carbon on the surface of the wood that serves as a natural layer of protection. The benefit of this technique over staining is that it is low-maintenance and will not fade over time.

A truly authentic application of this technique would have leave the wood planks with deep veins, which I didn't want in a modern application. The contractors instead used a blow torch to burn the surface, rinsed and scrubbed the planks, and repeated the process three times to achieve an even tone in the wood without over-burning it.

Blow-torching cedar siding. That looks like fun! (he had a big smile while he was doing this)

Rinse, scrub, and repeat

The result

It looks really nice on the house, and hopefully will be very low maintenance. I think that over time, the dark brownish tint of the siding coming up from beneath the carbon layer will fade to a grey and will still compliment the other materials on the house.